Method for optimizing lamp spectral output

Abstract

A lamp ( 10 ) includes a housing ( 12 ) with a light source ( 30, 32 ) disposed within the housing. Two or more light modulating elements ( 80, 82, 84, 86 ) are associated with different components of the lamp, such as a reflector housing ( 70 ), an envelope ( 36 ), a lens ( 74 ), and a shroud ( 76 ). Each of the light modulating elements modulates the visible light emitted by the source intermediate the source and an exterior of the housing. One of the light modulating elements modulates light in at least one region of the visible portion of the electromagnetic spectrum differently from another of the light modulating elements. In this way, the light emitted by the source may be tailored by using different properties of each of the light modulating elements.

1 . A lamp comprising: 
 a housing;    a light source disposed within the housing; and    a plurality of light modulating elements, each of the light modulating elements modulating the visible light emitted by the source intermediate the source and an exterior of the housing, a first of the light modulating elements modulating light in at least one region of the visible portion of the electromagnetic spectrum differently from a second of the light modulating elements.    
   
   
       2 . The lamp of  claim 1 , wherein at least one of the light modulating elements comprises an optical interference coating.  
   
   
       3 . The lamp of  claim 2 , wherein at least two of the light modulating elements comprise an optical interference coating.  
   
   
       4 . The lamp of  claim 3 , wherein the interference coating which comprises a first of the optical interference coatings differs from a second of the optical interference coatings in at least one of: 
 a number of optical interference layers;    a thickness of at least one of the optical interference layers; and    a composition of at least one of the optical interference layers.    
   
   
       5 . The lamp of  claim 1 , wherein the first light modulating element modulates the light in a first region of the visible spectrum and the second light modulating element modulates the light in a second region of the visible spectrum.  
   
   
       6 . The lamp of  claim 1 , wherein at least a portion of the light emitted by the source is modulated by both the first and second light modulating elements.  
   
   
       7 . The lamp of  claim 1 , wherein the lamp includes at least two of an envelope which surrounds the source, a shroud spaced from the envelope, a reflector, which reflects light from the source, and a cover lens which transmits light which has been reflected by the reflector and the first light modulating element is associated with one of the envelope, the shroud, the reflector, and the cover lens and the second light modulating element is associated with another of the envelope, the shroud, the reflector, and the cover lens.  
   
   
       8 . The lamp of  claim 7 , wherein the transmittance of the lamp at a given wavelength is given by the expression:  
       T SYSTEM (λ)=(C 2 ×T F ×MF F +[C 1 ×T F ×MF F ]×MF R )×MF CL    
     where C 1  and C 2  are constants indicating the relative amounts of energy emitted from the envelope which are directed toward and away from the reflector respectively; 
 T F =total light emitted by the envelope, prior to modulation;  
 MF F =a modulation function of a light modulating element associated with the envelope;  
 MF R =is a modulation function of a light modulating element associated with the reflector;  
 MF CL =is a modulation function of a light modulating element associated with the cover lens;  
 and wherein MF F , MF R  and MF CL  all differ by at least 5% for at least 10% of all wavelengths in the visible range of the spectrum.  
 
   
   
       9 . The lamp of  claim 1  wherein the light source comprises at least one of a filament and an arc discharge.  
   
   
       10 . A lamp comprising; 
 a housing;    a light source disposed within the housing; and    at least three light modulating elements, each of the light modulating elements modulating at least a portion of the light emitted by the source intermediate the source and an exterior of the housing such that light emitted by the lamp includes light modulated by the three light modulating elements.    
   
   
       11 . The lamp of  claim 10 , wherein at least one of the light modulating elements comprises an optical interference coating.  
   
   
       12 . The lamp of  claim 11 , wherein at least two of the light modulating elements comprise an optical interference coating.  
   
   
       13 . The lamp of  claim 10 , wherein the first light modulating element modulates the light in a first region of the visible spectrum and the second light modulating element modulates the light in a second region of the visible spectrum.  
   
   
       14 . The lamp of  claim 10 , wherein at least a portion of the light emitted by the source is modulated by the first, second, and third light modulating elements.  
   
   
       15 . The lamp of  claim 10 , wherein the lamp includes at least two of an envelope which surrounds the source, a shroud spaced from the envelope, a reflector, which reflects light from the source, and a cover lens which closes off an end of the housing and wherein the first light modulating element is associated with a first of the envelope, the shroud, the reflector, and the cover lens, the second light modulating element is associated with a second of the envelope, the shroud, the reflector, and the cover lens and the third light modulating element is associated with a third of the envelope, the shroud, the reflector, and the cover lens.  
   
   
       16 . A lamp comprising: 
 a housing;    a light emitting source disposed within the housing;    optionally, an envelope which surrounds the light source and which transmits at least a portion of the light from the source;    optionally a shroud, spaced outwardly from the envelope, which transmits at least a portion of the light from the source;    optionally a reflective surface which reflects at least a portion of the light emitted by the source;    optionally a cover lens which closes an end of the housing and which transmits at least a portion of the light emitted by the source;    a first optical interference coating associated with a first of the envelope, the shroud, the cover lens, and the reflective surface; and    a second optical interference coating associated with a second of the envelope, the shroud, the cover lens, and the reflective surface.    
   
   
       17 . The lamp of  claim 16 , further comprising: 
 a third optical interference coating associated with a third of the envelope, the shroud, the cover lens, and the reflective surface.    
   
   
       18 . A method of achieving a desired spectral distribution comprising: 
 modulating light emitted by a source with a first light modulating element;    modulating light emitted by the source with a second light modulating element, the second light modulating element being spaced from the first light modulating element o receive light modulated by the first light modulating component; and    outputting light modulated by at least the first and second light modulating elements to achieve light of the desired spectral distribution.    
   
   
       19 . The method of  claim 18 , wherein the modulation of the light with the first light modulating element includes changing the spectral distribution of the light and the modulation of the light with the second light modulating element includes changing the spectral distribution of the of the light.  
   
   
       20 . The method of  claim 18 , wherein at least one of the modulation with the first light modulating element and the modulation with the second light modulating element includes transmitting the light through an optical interference coating.  
   
   
       21 . The method of  claim 18 , wherein the first light modulating element is associated with a first lamp component selected from an envelope, a shroud, a reflective surface and a cover lens, and the second light modulating element is associated with a second lamp component selected from an envelope, a shroud, a reflective surface and a cover lens.  
   
   
       22 . The method of  claim 18 , further comprising modulating at least a portion of the light emitted by the source with a third light modulating element, the third light modulating element being spaced from the first and second light modulating elements.